ST. PETERSBURG — Ben Flower played tennis and paddled a kayak through the Chassahowitzka National Wildlife Refuge. He rode his bicycle to work at the University of South Florida's College of Marine Science and a Honda Shadow motorcycle on weekends. He led students on expeditions that bored into the ocean floor, retrieving sediment from thousands of years ago.

He moved between teaching geological oceanography and publishing in peer-reviewed scientific journals, between mentoring graduate students and bird watching. He was an expert in the history of climate change and the effects of the 2010 Deepwater Horizon oil spill.

All the while, Dr. Flower fought a rare genetic immune disorder that claimed the lives of three family members.

Dr. Flower, whose careful research was building him an international reputation among geologists, died Sunday, at Bayfront Medical Center. He was 49.

"He was highly respected as someone who took a very measured and thoughtful approach to difficult problems," said Jacqueline Dixon, dean of USF's College of Marine Science. "He had a knack for raising the right questions, and then methodically gathering together the right data to answer them."

David Hollander, a chemical oceanography professor with an office across the hall from Dr. Flower, called him a "strong advocate for sound science, for the science to speak for itself."

Most scientists who publish think humans play a significant role in climate change, and so did Dr. Flower, Hollander said.

To satisfy his many academic curiosities, he obtained research grants from the prestigious National Science Foundation and the Comer Foundation, published more than 50 peer-reviewed articles, and headed the Eminent Scholar lecture series sponsored by the Tampa Bay Times.

Dr. Flower was born in Palo Alto, Calif., and grew up in Northampton, Mass. As a graduate student at the University of California at Santa Barbara, he played a sport now called Ultimate (formerly Ultimate Frisbee), competing at a national level.

Dr. Flower started at USF in 1997 and was promoted to full professor earlier this year.

"He had an enduring love of science," said Eckerd College marine science professor David Hastings, who also went on kayak trips with Dr. Flower.

Dr, Flower was married and divorced. He remained close to his three children. His health suffered over the last 10 years due to common variable immune deficiency, which killed his mother and twin sisters. The deficiency led to lymphoma, colleagues say.

Dr. Flower maintained a sense of humor even in the hospital, and passed out tissues to teary visitors. He had not lived with the immune deficiency on his mind. "This thing wasn't even a consideration for how he was viewing the future," Hollander said. "There was no rearview mirror about his disease."

Andrew Meacham can be reached at ameacham@tampabay.com or (727) 892-2248.